Heat the oil in a large stock pot over medium heat. Add the onion and garlic and saute until the onion is cooked and translucent. Stir in the corn flour and cook for an additional one minute.
Pour in the chicken stock and stir to combine.
Add in the cooked chicken, enchilada sauce, black beans, corn, diced tomatoes, green chiles, salt and cumin. Stir until combined.
Heat over medium heat until the soup reaches a simmer. Let the soup simmer for 3 minutes stirring slowly.
Add in the cheese and stir until combined.
Serve with toppings of tortilla strips, sliced avocado, shredded cheese or sour cream.